kernel.git/arch/x86/boot/compressed, branch linux-4.8.y

x86/efi: Use efi_exit_boot_services()

2016-09-05T11:40:16Z

The eboot code directly calls ExitBootServices. This is inadvisable as the UEFI spec details a complex set of errors, race conditions, and API interactions that the caller of ExitBootServices must get correct. The eboot code attempts allocations after calling ExitBootSerives which is not permitted per the spec. Call the efi_exit_boot_services() helper intead, which handles the allocation scenario properly. Signed-off-by: Jeffrey Hugo Cc: Ard Biesheuvel Cc: Mark Rutland Cc: Leif Lindholm Cc: Ingo Molnar Cc: Signed-off-by: Matt Fleming

efi/libstub: Allocate headspace in efi_get_memory_map()

2016-09-05T11:18:17Z

efi_get_memory_map() allocates a buffer to store the memory map that it retrieves. This buffer may need to be reused by the client after ExitBootServices() is called, at which point allocations are not longer permitted. To support this usecase, provide the allocated buffer size back to the client, and allocate some additional headroom to account for any reasonable growth in the map that is likely to happen between the call to efi_get_memory_map() and the client reusing the buffer. Signed-off-by: Jeffrey Hugo Cc: Ard Biesheuvel Cc: Mark Rutland Cc: Leif Lindholm Cc: Ingo Molnar Cc: Signed-off-by: Matt Fleming

Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-07-26T00:32:28Z

Pull x86 boot updates from Ingo Molnar: "The main changes: - add initial commits to randomize kernel memory section virtual addresses, enabled via a new kernel option: RANDOMIZE_MEMORY (Thomas Garnier, Kees Cook, Baoquan He, Yinghai Lu) - enhance KASLR (RANDOMIZE_BASE) physical memory randomization (Kees Cook) - EBDA/BIOS region boot quirk cleanups (Andy Lutomirski, Ingo Molnar) - misc cleanups/fixes" * 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Simplify EBDA-vs-BIOS reservation logic x86/boot: Clarify what x86_legacy_features.reserve_bios_regions does x86/boot: Reorganize and clean up the BIOS area reservation code x86/mm: Do not reference phys addr beyond kernel x86/mm: Add memory hotplug support for KASLR memory randomization x86/mm: Enable KASLR for vmalloc memory regions x86/mm: Enable KASLR for physical mapping memory regions x86/mm: Implement ASLR for kernel memory regions x86/mm: Separate variable for trampoline PGD x86/mm: Add PUD VA support for physical mapping x86/mm: Update physical mapping variable names x86/mm: Refactor KASLR entropy functions x86/KASLR: Fix boot crash with certain memory configurations x86/boot/64: Add forgotten end of function marker x86/KASLR: Allow randomization below the load address x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G x86/KASLR: Randomize virtual address separately x86/KASLR: Clarify identity map interface x86/boot: Refuse to build with data relocations x86/KASLR, x86/power: Remove x86 hibernation restrictions

x86/mm: Enable KASLR for physical mapping memory regions

2016-07-08T15:35:15Z

Add the physical mapping in the list of randomized memory regions. The physical memory mapping holds most allocations from boot and heap allocators. Knowing the base address and physical memory size, an attacker can deduce the PDE virtual address for the vDSO memory page. This attack was demonstrated at CanSecWest 2016, in the following presentation: "Getting Physical: Extreme Abuse of Intel Based Paged Systems": https://github.com/n3k/CansecWest2016_Getting_Physical_Extreme_Abuse_of_Intel_Based_Paging_Systems/blob/master/Presentation/CanSec2016_Presentation.pdf (See second part of the presentation). The exploits used against Linux worked successfully against 4.6+ but fail with KASLR memory enabled: https://github.com/n3k/CansecWest2016_Getting_Physical_Extreme_Abuse_of_Intel_Based_Paging_Systems/tree/master/Demos/Linux/exploits Similar research was done at Google leading to this patch proposal. Variants exists to overwrite /proc or /sys objects ACLs leading to elevation of privileges. These variants were tested against 4.6+. The page offset used by the compressed kernel retains the static value since it is not yet randomized during this boot stage. Signed-off-by: Thomas Garnier Signed-off-by: Kees Cook Cc: Alexander Kuleshov Cc: Alexander Popov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Aneesh Kumar K.V Cc: Baoquan He Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Christian Borntraeger Cc: Dan Williams Cc: Dave Hansen Cc: Dave Young Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: Jan Beulich Cc: Joerg Roedel Cc: Jonathan Corbet Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Lv Zheng Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Fleming Cc: Peter Zijlstra Cc: Stephen Smalley Cc: Thomas Gleixner Cc: Toshi Kani Cc: Xiao Guangrong Cc: Yinghai Lu Cc: kernel-hardening@lists.openwall.com Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/1466556426-32664-7-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar

x86/mm: Refactor KASLR entropy functions

2016-07-08T15:33:45Z

Move the KASLR entropy functions into arch/x86/lib to be used in early kernel boot for KASLR memory randomization. Signed-off-by: Thomas Garnier Signed-off-by: Kees Cook Cc: Alexander Kuleshov Cc: Alexander Popov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Aneesh Kumar K.V Cc: Baoquan He Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Christian Borntraeger Cc: Dan Williams Cc: Dave Hansen Cc: Dave Young Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: Jan Beulich Cc: Joerg Roedel Cc: Jonathan Corbet Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Lv Zheng Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Fleming Cc: Peter Zijlstra Cc: Stephen Smalley Cc: Thomas Gleixner Cc: Toshi Kani Cc: Xiao Guangrong Cc: Yinghai Lu Cc: kernel-hardening@lists.openwall.com Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/1466556426-32664-2-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar

x86/KASLR: Fix boot crash with certain memory configurations

2016-07-08T12:36:19Z

Ye Xiaolong reported this boot crash: | | XZ-compressed data is corrupt | | -- System halted | Fix the bug in mem_avoid_overlap() of finding the earliest overlap. Reported-and-tested-by: Ye Xiaolong Signed-off-by: Baoquan He Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

x86/efi: Remove unused variable 'efi'

2016-06-27T11:06:55Z

Remove unused variable 'efi', it is never used. This fixes the following clang build warning: arch/x86/boot/compressed/eboot.c:803:2: warning: Value stored to 'efi' is never read Signed-off-by: Colin Ian King Signed-off-by: Matt Fleming Cc: Ard Biesheuvel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1466839230-12781-4-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar

x86/KASLR: Allow randomization below the load address

2016-06-26T10:32:05Z

Currently the kernel image physical address randomization's lower boundary is the original kernel load address. For bootloaders that load kernels into very high memory (e.g. kexec), this means randomization takes place in a very small window at the top of memory, ignoring the large region of physical memory below the load address. Since mem_avoid[] is already correctly tracking the regions that must be avoided, this patch changes the minimum address to whatever is less: 512M (to conservatively avoid unknown things in lower memory) or the load address. Now, for example, if the kernel is loaded at 8G, [512M, 8G) will be added to the list of possible physical memory positions. Signed-off-by: Yinghai Lu [ Rewrote the changelog, refactored the code to use min(). ] Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Baoquan He Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: H.J. Lu Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1464216334-17200-6-git-send-email-keescook@chromium.org [ Edited the changelog some more, plus the code comment as well. ] Signed-off-by: Ingo Molnar

x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G

2016-06-26T10:32:05Z

We want the physical address to be randomized anywhere between 16MB and the top of physical memory (up to 64TB). This patch exchanges the prior slots[] array for the new slot_areas[] array, and lifts the limitation of KERNEL_IMAGE_SIZE on the physical address offset for 64-bit. As before, process_e820_entry() walks memory and populates slot_areas[], splitting on any detected mem_avoid collisions. Finally, since the slots[] array and its associated functions are not needed any more, so they are removed. Based on earlier patches by Baoquan He. Originally-from: Baoquan He Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Baoquan He Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: H.J. Lu Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Yinghai Lu Link: http://lkml.kernel.org/r/1464216334-17200-5-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar

x86/KASLR: Randomize virtual address separately

2016-06-26T10:32:04Z

The current KASLR implementation randomizes the physical and virtual addresses of the kernel together (both are offset by the same amount). It calculates the delta of the physical address where vmlinux was linked to load and where it is finally loaded. If the delta is not equal to 0 (i.e. the kernel was relocated), relocation handling needs be done. On 64-bit, this patch randomizes both the physical address where kernel is decompressed and the virtual address where kernel text is mapped and will execute from. We now have two values being chosen, so the function arguments are reorganized to pass by pointer so they can be directly updated. Since relocation handling only depends on the virtual address, we must check the virtual delta, not the physical delta for processing kernel relocations. This also populates the page table for the new virtual address range. 32-bit does not support a separate virtual address, so it continues to use the physical offset for its virtual offset. Additionally updates the sanity checks done on the resulting kernel addresses since they are potentially separate now. [kees: rewrote changelog, limited virtual split to 64-bit only, update checks] [kees: fix CONFIG_RANDOMIZE_BASE=n boot failure] Signed-off-by: Baoquan He Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: H.J. Lu Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Yinghai Lu Link: http://lkml.kernel.org/r/1464216334-17200-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar